Artificial leg



UNITED STATES PATENT OFFICE.

BENJN. W. JEWETT, OF GILFORD, NEW HAMPSHIRE.

ARTIFICIAL LEG.

Specification of Letters Patent No. 16,360, dated January 6, 1857.

To all whom it may concern:

Be it known that I, BENJAMIN W. JEW- ETT, of Gilford, in the county ofBelknap and State of New Hampshire, have invented new and usefulImprovements on Artificial Legs; and I do hereby declare that thefollowing is a full, clear, and exact description thereof, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon, of which said drawings- Figure one is a longitudinalsection of the limb, Fig. 2 is a view of the bolt of the knee joint,Fig. 3 of the bolt of the ankle joint, and Fig. 4 of the strap by whichthe bolts are fastened firmly in their places.

In Fig. 1, A represents the foot, B, the leg, and C, the thigh. B is soconstructed that its lower end overlaps at the ankle the.

foot A upon all sides, as indicated by the dotted line I. In Palmersartificial leg the leg overlaps the foot behind, and the foot the legbefore, and in that leg there is an opening in the top of the foot whichallows the dirt and perspiration access to the spring in the foot. Byconstructing it in the way above mentioned, even if the foot beconstructed like that of Mr. Palmers, there is inconvenience from thissource. But the foot is not so constructed. E is a spiral spring, oneend of which is inserted into the foot, and the other end pressesagainst the toe, which turns upon the hinge at F. The toe is kept downby the operation of this spring and is prevented from opening too far bythe bottom of the toe striking the foot at 71. D is another spiralspring inserted into'the hollow of the foot, to which is attached a cordterminating in a metallic rod marked K, which is fastened to thecrossbrace O, passing across the leg, by the hook L. Its otfice is torestore the foot to its proper position after being drawn down by theaction of the tendo Achillis J, J. The tendo Achillis is inserted firmlyinto the heel; on emerging therefrom it branches into two parts, one ofwhich passes upon each side of the interior of the leg through aperturesin the bottom of the thigh, at the knee, and are firmlysecured there atV. H, the dotted line is a prolongation of the leg, there being two, oneon each side of the foot, whose office is to support the bearings of theoint, and thereby attach the foot to the leg. Through theseprolongations and through the foot passes the bolt Gr, shown in Fig. B.These bolts are made square at the ends so as to fit into correspondingapertures in the straps which attach them to the limb as in X, Fig. 4,to obviate a difficulty in the joint as constructed in Mr. Palmers leg,in that the bolt is attached to the strap, and prevented from turning bytwo small screws passing through the bolt head into the strap, on oneside of the head, and the constant'strain causes them to get loose andwork unsteadily. These bolts in my invention also passes through boxesof Babbitt or other suitable metal. In Palmers leg the aperture throughwhich the bolt passes is sheathed with buckskin glued on to the wood;the expansion of the wood by heat causes it to pinch the bolt andrenders it necessary to lubricate the joint; and for this purposeta-llow must be used as a softer material would ofiset the glue andloosen the buckskin. In cold weather this joint becomes so stiif that itis necessary to warm it before it will move easily. To remove thisinconvenience I devise the metallic box which incloses the bolt. Y Y arescrews passing through the prolongations of the leg H for the purpose ofpreventing the foot from moving upward or downward too. far. N is a cordpassing around the cross bar 0, and there secured by the cap M. One endof this cord passes up on each side of the interior of the leg, a littleback of the tendo Achillis through apertures in the knee and is attachedto the thigh at W. It prevents the thigh from tilting too far forwardand strengthens the limb. Q, is a bent spring firmly secured to thecross brace P, and having at the end a rod B, passing up through anaperture in the cross brace P, through a slot in the knee into the thighto which it is attached "by the hook S. It tends to throw the legforward. T is the bolt of the knee joint, shown at Fig. 2. The dottedline U shows the outside of the top of the leg.

Fig. 2, is a representation of the bolt of the knee joint. A is thecircular head of the bolt; 6, 5 squares fitting the straps (shown atFig; 4) 0, the body of the bolt, slightly tapering; (Z, a screw passinginto the end and securing the bolt in its place.

Fig. 3 is the bolt of the ankle joint and may be made in that form, orin the form of Fig. 2. The tendo Achillis J and the cord N are made oflinen, covered with buckskin. I substitute the use of linen for catgutin these cords because it is more flexible,

and in case of amputations below the knee is not so much affected by theperspiration as the gut is. These cords pass up through apertures in thebottom of the thigh, around which the wood is not cut away, and arefastened at V and W by blocks of wood fitting into sockets in thewoodwork, in which sockets the apertures through which the cords passterminate. By the use of the spiral springs E and D I avoid the use ofthe large spring used in Palmers leg, which requires a great deal of thein terior of the foot to be cut away, thereby weakening it and'tendingto cause it to break at the ankle, and I avoid also the use of the cordpassing from the spring beneath the foot over the joint of the toe, inPalmers leg, which is liable to be worn off, and besides this, from itsconstruction, the spring is apt to break, and it would deface the footto remove it. And if it were necessary to remove the toes, as it oftenis, it would be necessary to make new ones in Palmers leg, whereas in myfoot the toes can be removed and replaced without inury.

By the use of the bent spring Q, and its adjuncts I avoid the use of thecumbersome spring and lever in the thigh of Palmers leg, which can notbe used in case of a long stump to the thigh, and renders necessary theapplication of an elastic strap on the outside. In my invention everypart is so constructed as to be easily removed for repair, while inother artificial legs there is great difliculty in this, so much so thatit must be sent to the manufactory for repairs even the most trivial.

I do not claim the tendo Achillis J, but

WVhat I do claim and desire to secure by Letters Patent, is: v

l. The spiral spring D in combination with the rod K, hook L andcross-brace O.

2. The method of attaching the tendo Achillis J and the cord N to thethigh by the use of the pins V and W.

3. The bolts G and F, Figs. 2 and 3, in combination with the straps,Fig. 4, and their metallic boxes; all for the purposes hereinbeforespecified and operating substantially in the manner as hereinbefore setforth.

BENJAMIN W. JEWETT. Witnesses:

J. P. Momuson, C. S. GALE.

